SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f36f4fbf38e44cddb7b8d8604dcd80a0278c01a0278d04f5d9e132a14d04546' 
  AND token = 'glktKvmT43lpfsRf+3yeUJlOiGOwdja4i5pg8EVBe4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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