SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '43f4be472f3f8a06cfdd1bdb767895da6bfbfc40503d5bf87fdb4159b32bbd21' 
  AND token = 'txI/XqRM1PbVQ4KkIT2HCuG2hkh4AzjJMlrDOWI38MM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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