SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4a0665b227f7787638b21fc2b76bcab7c52398021ab06ecbcdf332cec898ef6' 
  AND token = 'B4qxuTZfeGjaCISJjwB2EfRZJCTvVnQGUj92FhFk5Tw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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