SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e4788e6434325af25aa610c10536c1f5afb996a6aa2f3ef235d846601757ee9' 
  AND token = 'wzbRXlkbhdHZ9ohdLAizFRQ5h7d3+SpKdR73BIRpWrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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