SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c15d769436b561196f8546572d4cd51c6dba0a842ed3d2c83490a57747b5a6d' 
  AND token = '23Fzqui7vbMwOgrxS7hYDBJ2pZXDQ3Kbp8+IFH08brI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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