SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1331dfe14836ed5c073e0906aae398149157c6accb78754b4f453fe50eb4fbc0' 
  AND token = '6kDDiileR+yrGcHSqogpc0/d/CC7xZpEvREbp5XWFlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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