SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f40828cee508e0bea2a9097f278075f49faa024f03d8fd06c5457ed207edcea2' 
  AND token = '+/iIlc6uBgmWWhSNVKLe7Zvzxmv+6YP3eCooNkpk+9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}