SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e06abb941f063cb396a098f496417b45bbd8657e9d178e4ad27548eb59004d39' 
  AND token = 'g/+qeUK2xA7yzS4QI++UVZoBI14icpNTrwEuOji4hwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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