SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fd6461a5f15ba4d9ee1170e0d5b857f65e06525b6333f56ad83de8a1e95f738' 
  AND token = 'YIEqELiT141nQRjKHlKNqfrAMAQBTVT4taut/ypT3Xo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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