SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '164709361897bc90b779415f44a4a82d91f76a51e43893d25b5abee2c6959ab3' 
  AND token = 'iIQONCnYfSZAnuM6fBrsoFRPMzQnI69yZCZpBa3ZNy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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