SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a3b693b5271da4fecac40fe1e48da660ed6a78c33605a8d0b339d3a11869c68' 
  AND token = 'j1TJgfpcq2vDkyePHb+oXttiLPjrP2NKkzbQ9IJi+aE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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