SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5be5f634d4b18b30de053396deff766ff5d7febcd10922a2f190eaa4d48546f2' 
  AND token = 'oHTDM3kssFj6IpbKySpScpLZ1RYlFp7CX3nfbdHNKaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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