SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f9c8bdfe6dc744366346e668dcd93e81c6ba6af83041bb035742ae4dc249c83' 
  AND token = 'Uux21jeuVLlp0RpgD/XR5LM95r8n2hmw2Nq11EGCdUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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