SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bed84dd2ef03c6685d1357b0753a7eb710d412cd7512d47b4b84b93a86dc2a17' 
  AND token = 'gsmFn4phYs+uFUGlnS69CEUDPaO5/6PbCR5+4PWw1yQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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