SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a377a540e872ea0504d60dc0f80f32fac9449b43aaa77017261f4d3d39758a6' 
  AND token = 'oDcopTdRhdsw4ePF4XN2I284dAYMcG0IzynpGsean2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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