SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76e236e01ae5ad4b5e4493d0af6315ce53a03ba98fd6679bb5072e5c71c05879' 
  AND token = 'pa/kMoLfSx/CvobgM31qAwOZcR6WqS3VapuSsc4Ggzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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