SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3b8285dcec636a3718595789130ca7a2dacd8c2949f8a05070eba2b5d7a000c' 
  AND token = 'JDAQS3C0E4NXUUvGv5TSReeZsNJcWYt9M2SqG74usAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}