SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '620c38ca7e5467c692d4c16dcc8e268ccd102f10b9d6acd5a872eedb615dbb98' 
  AND token = 'c2lea09lEzMuUVxVFheqwNaAOHueuapTB4fitaerOw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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