SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4becc7512f3583fb539767e2496916b499386c0a41313ef926a2b5cde5bd9a7b' 
  AND token = '4HtW/Na85yK8iRiqfkssRNgDEh9unRDmLp6PqvLVRL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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