SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e25bf72bfd6b65ca04beacc7f8148642e959082367f5ecd4b0f84e4d47a50167' 
  AND token = 'ZJUC+QtyMGuE9vlRoL6MnyvMZmQZuwYdiNKBBw3khdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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