SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4189cefc57a902b36267df0f9ac3302258428d9cd1caa5b6338b543da99ee724' 
  AND token = '/dLMzOHfUJm/ugLORvGhVi2YYwO9jDmK3ILTv/aLDfk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00072

JSON explain

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