SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '08340d740bc893f64bab09427fdc3457fc709403898e435a38315e7497df1b2a' 
  AND token = 'ynuG96KhaiV8HKHjumk0DU56N6hIlpqQ3r7xX0+vNFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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