SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a26fb533a160a558559c04c1c7dde7cade4ad058c529f579cde19e3593243d29' 
  AND token = 'CptWEZFDSV+dIZ8iReamOzwxX7V409vmO7SuhnLosEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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