SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56ce5f78717c812c96e0ac2aade888ef1440b22b2500e888c6c48917e4026615' 
  AND token = 'NmwAcEtGG5nmCK6AEX10FhbJoNlcNvce89uWIIMm54A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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