SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '087051f77cacba2bc2abe1a77670a5e7499fbbdee76f121b652b373be7d4f03a' 
  AND token = 'RlVAgNx7hj0fVi3UzKVR4Uh5HOtLgrPvC7ZezqOrXu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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