SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9c5e792ca9e0e23754426dedee4d6cfc37842b68793053a7c18792836b1bd28' 
  AND token = 'yYThj7NItrJdSqzCJPwivPE68XpM7hVDcIon5o/4ECw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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