SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9918153c65929eef34754ea5b98616c76345e450d1b2f096cc3e470156604347' 
  AND token = 'gx31n3HgPXuMfq3dxGnBAde7/sp8/ZnsHBZhegjcQC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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