SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '187e8517d359db669b7095bbee4fa8d083e96792d14dc62975ba543b0a4af97c' 
  AND token = 'wHqM1ef93blQ3kxx9U5tZo2xaAxjqwVulAi/ABkn/UE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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