SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f3c937b77010eb821139a31af483c55edf0b9f6e0bba4979412a639c59d5de3' 
  AND token = 'JfWm8Q9oB6ei3N1lhTJaCRGwMGDhHPIAmEgu3fbANLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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