SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c2c982456c21c0fefebb1af602d2ce5009da212189bb484a753bfddc10eb397b' 
  AND token = 'Qv7YmToPa1zaKCL1qN6a9t3cqAH7rrqiiIFUiLOwseM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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