SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c564e3598dd2a902c5c050225513238d88fee5f6168bdddf47f3a5674aceec6b' 
  AND token = 'Fcy9DBlVEBa6kXcIF47n1mSTRTQN/RSM5hwj1W2pL88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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