SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8224dad4e3d528bb51fe966b4512dce485d8b007479695f901f358e0cf98e9a6' 
  AND token = '7hKs5Ha8eJQp/Utk/Ps2Ic7rUuPIKAk1cPUzFgJa1Go=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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