SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b6b709c494ae819be2797bc6480770c7f92ef0f8150a143f93c1a24f5e1490e' 
  AND token = 'BFBFDXAdfzXXI6pxvCmP2OEtRUzauht2GQuZw5auZ1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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