SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b3792c0c15f174ad79ee2fcfd18058bd47706b0f1795f8639e80fcf5e01fb78' 
  AND token = 'IhvKP8WObx8EpryUhRINdYpXea15zn1DwHGkHOhsH0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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