SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d034632a60359f85352ee425fe97dbb14a38376e6648e27a008d3732cf42f5e' 
  AND token = 'vsua3cF/AY6S6Op7nH44KGi53NXLzuMOyjMUSC7ZijY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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