SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc6f3a824698ac86028b355bacc3911266b9f008395329ab65ec13e172691ab7' 
  AND token = 'OWpEu0Z79tuiTy+Np115em+NezPOWGD72QAG6LcqZ0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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