SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '764d1f66bad4df62a77ceda4c40aff17946ba2fa590ee7df13a10ec9e1a0204a' 
  AND token = 'SyDr4ustM5T/CFawCgWJPw/tGn45BWlAvag5nAglU+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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