SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc9d55100bc5dfa85bf4556fff9dd2ad4c34b99c78f3d2632585131eeb33a256' 
  AND token = 'zLhbXPKLkxSKBUpdLgjsRTEEqrlGadda5kWpR44MjiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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