SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd6659abf4d09026962687cc3cd2edd75b6ff7886f544ee7c51ba862cffba3e1' 
  AND token = 'E+ughU1j/wnSYyCEKmBRsuqwNByrXjdJystlo88XzbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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