SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b0f1c121ea538a670ba53ad7edf6a7f4b353283b353ea13476d189d234f94374' 
  AND token = 'rHJ2j/HusYM57e6HuPQclGB75fBxDtNJThhRNH+IiFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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