SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5fb910e4a5bd26b0150ff1f5dc7ccdad2aa49a47a2449cd380ab4164483a032' 
  AND token = 'stvrgBJOf0FjzBvzq1i06zlDrO5x1JtwDdkZnyfvCiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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