SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e60004874b714908cc8bcafabcfed9d2992265bceb06caaf89556f9c06128818' 
  AND token = 'EYbMhoBcjudfOlFGCbr0k+Lc3fEHZR6iCvAcfHrr4/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}