SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70765f54fdaafab2424a35083db7066442ced83332d22f63af0a4a0401c63bc4' 
  AND token = 'baf0ONy5XENsTt+iR/2ENkqIpRby/gsB97gZLtnvesU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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