SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2d8bdf6f4639648acc7554c6a0950179fa6c497a6cccb9179eaa8a8c408985b' 
  AND token = '4xX7VwSA1oxXkoHz/kxe6DTbc1mtPy1s2YaGpNP2iLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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