SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7ea0dd37944cdc27c80b43ef8ec460d440f1034266c588124b4de6fca94e1f2' 
  AND token = 'RoQqWK5Fz9JacrOZVAV+Tgg5jWhsIDPIq3Z/gXLtelo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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