SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '902fb212e2c812f47fde7bff46c39d1c3f6eeee4b2cc082efaee2e7a337d25ec' 
  AND token = 'fj89ip89YpEE/DWLNPVuK+6kbcWT5yZ/EigAy+Brabs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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