SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '76dc964492aa29e1405a6b9ac22c4d06963ceb1acf04f31efce0a0384e853d76' 
  AND token = 'tIGNOvQSnbzYr5ui6nj/nRf7YPLVmZ8QQ+Vrtqb8YQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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