SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf18801916ffa214cb5546df4db996e4cb6e0a8dacf9e0fab517f138d98cf2e4' 
  AND token = '7n2jWoYB0AQ0S4UyO4sbdSOZ/XmoJToF9a/Mupgtlw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00195

JSON explain

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