SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac756001242503958e7b0c85816bdc835d08d858487f3b1ed751fb38242d39ab' 
  AND token = 'ZVj1oT+xqTBQpRyHE+zAutax/+czXJPII/wgLIT4in8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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