SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd24907df5ce0066226d87564d496cec353720951991c0649cc00aa48860d72d2' 
  AND token = 'r5czTL2V70pjxGCBHTJHB8NH5BPmi+mtBB+tZfM6ZPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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