SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2dc67e854075a51e834aecf24ecf204f5a77147abfafbc02c0e6ad7815931082' 
  AND token = 'eNR0w9aDPuluReDrzL2FkMspqUr4VrhUhl1aPAyLXAk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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