SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '592377d64190a08a4d44267c683868d77469f1442b1d131fc774a4ed6bffe10c' 
  AND token = 'sy/bF/igGhBXvagk91PxgfNewOeFNLZntsG/iYmUhVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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