SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1b8227bdb937c40b9fa961087009764f2e293eac9f5d97579761ebe04cb993f' 
  AND token = 'Rptwa3+MUc//uD61YAPkpO09NkxdLGidQ4jef1gKGFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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