SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2e6c8e35d0f317a550af8902ce35f0cb3329b6307bc948bc8874122dab0a8e3' 
  AND token = 'a2wM9Nbs/PR9ZmaLRFod0xL45FT3DFilPvR5imQHPzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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