SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f67191b3c42cbdfb1bfabbfd935c5f37369a258cb730c7cde74a10552cbec3e4' 
  AND token = 'mnDhlq2WZkej4RVjYL5wEtVmLxODt70fBIg1mLgllzc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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