SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3a1117d23489e8dbb30a169ce243d60d04a0cd00fbbf45ebb14a77520257abe5' 
  AND token = 'CBMCUVIc9i4/2h0s92SJvvplm7erJUssNW8wS7Qi6xc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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