SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08b50c9cd4c0e274f51a74ffec636fc12861c30ea07a4282791cded3e10e0478' 
  AND token = 'JYX2p9WpY3akM/FvBE6XZNtnIRxG3wSWy1BiMmQ2yIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}