SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c080b6e0fb06a73493d2bc5a68d4b4cdf43f0b4ee7a723acc48ad40fefffc4f' 
  AND token = 'Q8xsPg0SL7TWlB/DlALVQfph64ARFA/JSDMtXPxex44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}