SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef803823f0e9e02f1c3395385accb4276032e03fce2374ade398cd34f943648a' 
  AND token = 'iMPlfwQtLX7+2/d3Ge11VVGupQo0oUv0WhClzDJdTgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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