SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eaf0eea31ca9539f181dbd3b3236716c7d843e38ae0dcba29e027c65f740402c' 
  AND token = 'aioj8XeBrLApntTapXUxLa7iecD34sfLjtdBXE3QzQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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