SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2930c289d49cd89f7e116dc823abc590941dba7788376332efecba6b54cfc3c' 
  AND token = '5NyMRqWHNWrFord/8MgDoozzd7tbQy+GyrF6OxgEf/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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