SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f03fb2e5918bf447818f80e124b94fbe7928e9eb76dde3dd0c62ef4d094d3f3b' 
  AND token = 'eauoGSOYZJ9UYWOW+3ths3vx24pCjTaykvUVGMaXEGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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