SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7616323db39a4f04855366d752c8def817fbc8ed599e92c3bcb2c56f71a7b6b' 
  AND token = 'MijMViOReiB1N/3eVjRBGoedZw8yAxkvZCNwJ1YqBgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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