SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d8f58bd698adfd4396484e7fa58eef048d91c75a8d949d6927e9a4c09e206b6' 
  AND token = 'zVprxwsEp2QuvZEpc+ygR/rSlGfcFo8H2mXxFjB7vA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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