SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2dd89095ee819ffcc9e48a8e7c8db7c4e75068f7274335a963f65422ef93237' 
  AND token = 'yKhXw7IDhmBpH2mnIKaJLudLslRCHLMoJc24xnUeM0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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