SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a906812ebd6f534c3f3f0aa5d6fdff6b4106708828cba9c2a0127950eddb9dc0' 
  AND token = 'Qstk4WPVyZTb7tPMoREyIGYjEsEpfK42iJxhkdiZ5ms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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