SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12c649970937c720345b2a0b4b95ff9c44bc17c6aa9cbcb255122e864c2903d8' 
  AND token = 'jKh2FsAkAkLS4K4T3tZAUJO1DYvfjWa/xMTPWkm+UxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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