SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c6b1f262b6e8816a7947dfde6d0461762afc54df4115f4ab44fd8b10e4fe1d4' 
  AND token = 'GRjplTH6PpFkvWQNgYkIjm7tGpG8/Bhx6yGCiWwtZuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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