SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11f9511bf4a227648e7d19a25f5fcae6bc17f1aef7017795eb4515c5aaee557b' 
  AND token = 'fHsEenhaRHSIVLgwsDlfDSLT6vOdA+K6UxoOmt6/g50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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