SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56863102645b6ab0a7dd74c353221637e779b6d8d6e287ed8ff2d8c078c22633' 
  AND token = 'S6RNceYbCiGXpUFLYwuV5l45/HzkuROmXDKs25JaB+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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